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<li class="chapter" data-level="1" data-path="data-read-write-description.html"><a href="data-read-write-description.html"><i class="fa fa-check"></i><b>1</b> 数据导入导出</a>
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<li class="chapter" data-level="1.1.3" data-path="readxl-description.html"><a href="readxl-description.html#batch:read"><i class="fa fa-check"></i><b>1.1.3</b> 批量读取</a></li>
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<li class="chapter" data-level="1.2.1" data-path="writexl.html"><a href="writexl.html#writexl:usage"><i class="fa fa-check"></i><b>1.2.1</b> 用法</a></li>
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<li class="chapter" data-level="1.3" data-path="openxlsx-description.html"><a href="openxlsx-description.html"><i class="fa fa-check"></i><b>1.3</b> openxlsx</a>
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<li class="chapter" data-level="1.3.1" data-path="openxlsx-description.html"><a href="openxlsx-description.html#openxlsx:install"><i class="fa fa-check"></i><b>1.3.1</b> 安装</a></li>
<li class="chapter" data-level="1.3.2" data-path="openxlsx-description.html"><a href="openxlsx-description.html#openxlsx:functions"><i class="fa fa-check"></i><b>1.3.2</b> 基础功能</a></li>
<li class="chapter" data-level="1.3.3" data-path="openxlsx-description.html"><a href="openxlsx-description.html#定制格式输出"><i class="fa fa-check"></i><b>1.3.3</b> 定制格式输出</a></li>
<li class="chapter" data-level="1.3.4" data-path="openxlsx-description.html"><a href="openxlsx-description.html#函数参数"><i class="fa fa-check"></i><b>1.3.4</b> 函数参数</a></li>
<li class="chapter" data-level="1.3.5" data-path="openxlsx-description.html"><a href="openxlsx-description.html#总结"><i class="fa fa-check"></i><b>1.3.5</b> 总结</a></li>
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<li class="chapter" data-level="1.4" data-path="readr-package.html"><a href="readr-package.html"><i class="fa fa-check"></i><b>1.4</b> readr</a>
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<li class="chapter" data-level="1.4.1" data-path="readr-package.html"><a href="readr-package.html#readr:install"><i class="fa fa-check"></i><b>1.4.1</b> 安装</a></li>
<li class="chapter" data-level="1.4.2" data-path="readr-package.html"><a href="readr-package.html#readr:usage"><i class="fa fa-check"></i><b>1.4.2</b> 用法</a></li>
<li class="chapter" data-level="1.4.3" data-path="readr-package.html"><a href="readr-package.html#readr:write-function"><i class="fa fa-check"></i><b>1.4.3</b> 导出功能</a></li>
<li class="chapter" data-level="1.4.4" data-path="readr-package.html"><a href="readr-package.html#总结-1"><i class="fa fa-check"></i><b>1.4.4</b> 总结</a></li>
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<li class="chapter" data-level="1.5" data-path="data-vroom.html"><a href="data-vroom.html"><i class="fa fa-check"></i><b>1.5</b> vroom</a>
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<li class="chapter" data-level="1.5.1" data-path="data-vroom.html"><a href="data-vroom.html#安装"><i class="fa fa-check"></i><b>1.5.1</b> 安装</a></li>
<li class="chapter" data-level="1.5.2" data-path="data-vroom.html"><a href="data-vroom.html#用法"><i class="fa fa-check"></i><b>1.5.2</b> 用法</a></li>
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<li class="chapter" data-level="1.6" data-path="data-rstudio-addins.html"><a href="data-rstudio-addins.html"><i class="fa fa-check"></i><b>1.6</b> Rstudio导入</a>
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<li class="chapter" data-level="1.6.1" data-path="data-rstudio-addins.html"><a href="data-rstudio-addins.html#rstudio-工具栏导入"><i class="fa fa-check"></i><b>1.6.1</b> rstudio 工具栏导入</a></li>
<li class="chapter" data-level="1.6.2" data-path="data-rstudio-addins.html"><a href="data-rstudio-addins.html#插件导入"><i class="fa fa-check"></i><b>1.6.2</b> 插件导入</a></li>
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<li class="chapter" data-level="1.7" data-path="data-file-path.html"><a href="data-file-path.html"><i class="fa fa-check"></i><b>1.7</b> 文件路径</a>
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<li class="chapter" data-level="1.7.1" data-path="data-file-path.html"><a href="data-file-path.html#指定路径"><i class="fa fa-check"></i><b>1.7.1</b> 指定路径</a></li>
<li class="chapter" data-level="1.7.2" data-path="data-file-path.html"><a href="data-file-path.html#默认路径"><i class="fa fa-check"></i><b>1.7.2</b> 默认路径</a></li>
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<li class="chapter" data-level="1.8" data-path="data-expand.html"><a href="data-expand.html"><i class="fa fa-check"></i><b>1.8</b> 拓展</a>
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<li class="chapter" data-level="1.8.1" data-path="data-expand.html"><a href="data-expand.html#tidyxl:package"><i class="fa fa-check"></i><b>1.8.1</b> tidyxl</a></li>
<li class="chapter" data-level="1.8.2" data-path="data-expand.html"><a href="data-expand.html#参考资料"><i class="fa fa-check"></i><b>1.8.2</b> 参考资料</a></li>
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<li class="chapter" data-level="2" data-path="Data-Manipulation-dplyr.html"><a href="Data-Manipulation-dplyr.html"><i class="fa fa-check"></i><b>2</b> 数据处理之-dplyr</a>
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<li class="chapter" data-level="2.1" data-path="dplyr-description.html"><a href="dplyr-description.html"><i class="fa fa-check"></i><b>2.1</b> 前言</a>
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<li class="chapter" data-level="2.1.1" data-path="dplyr-description.html"><a href="dplyr-description.html#dplyr:install-package"><i class="fa fa-check"></i><b>2.1.1</b> 安装</a></li>
<li class="chapter" data-level="2.1.2" data-path="dplyr-description.html"><a href="dplyr-description.html#dplyr:difference-of-sql"><i class="fa fa-check"></i><b>2.1.2</b> Excel and Sql 类比</a></li>
<li class="chapter" data-level="2.1.3" data-path="dplyr-description.html"><a href="dplyr-description.html#常见问题"><i class="fa fa-check"></i><b>2.1.3</b> 常见问题</a></li>
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<li class="chapter" data-level="2.2" data-path="dplyr-usage.html"><a href="dplyr-usage.html"><i class="fa fa-check"></i><b>2.2</b> 基础用法</a>
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<li class="chapter" data-level="2.2.1" data-path="dplyr-usage.html"><a href="dplyr-usage.html#dplyr-filter"><i class="fa fa-check"></i><b>2.2.1</b> filter</a></li>
<li class="chapter" data-level="2.2.2" data-path="dplyr-usage.html"><a href="dplyr-usage.html#dplyr-select"><i class="fa fa-check"></i><b>2.2.2</b> select</a></li>
<li class="chapter" data-level="2.2.3" data-path="dplyr-usage.html"><a href="dplyr-usage.html#dplyr-rename"><i class="fa fa-check"></i><b>2.2.3</b> rename</a></li>
<li class="chapter" data-level="2.2.4" data-path="dplyr-usage.html"><a href="dplyr-usage.html#dplyr-relocate"><i class="fa fa-check"></i><b>2.2.4</b> relocate</a></li>
<li class="chapter" data-level="2.2.5" data-path="dplyr-usage.html"><a href="dplyr-usage.html#dplyr-mutate"><i class="fa fa-check"></i><b>2.2.5</b> mutate</a></li>
<li class="chapter" data-level="2.2.6" data-path="dplyr-usage.html"><a href="dplyr-usage.html#dplyr-arrange"><i class="fa fa-check"></i><b>2.2.6</b> arrange</a></li>
<li class="chapter" data-level="2.2.7" data-path="dplyr-usage.html"><a href="dplyr-usage.html#dplyr-summarise"><i class="fa fa-check"></i><b>2.2.7</b> summarise</a></li>
<li class="chapter" data-level="2.2.8" data-path="dplyr-usage.html"><a href="dplyr-usage.html#dplyr-groupby"><i class="fa fa-check"></i><b>2.2.8</b> group_by</a></li>
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<li class="chapter" data-level="2.3" data-path="dplyr-functions.html"><a href="dplyr-functions.html"><i class="fa fa-check"></i><b>2.3</b> 常用函数</a>
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<li class="chapter" data-level="2.3.1" data-path="dplyr-functions.html"><a href="dplyr-functions.html#条件判断"><i class="fa fa-check"></i><b>2.3.1</b> 条件判断</a></li>
<li class="chapter" data-level="2.3.2" data-path="dplyr-functions.html"><a href="dplyr-functions.html#case_when"><i class="fa fa-check"></i><b>2.3.2</b> case_when</a></li>
<li class="chapter" data-level="2.3.3" data-path="dplyr-functions.html"><a href="dplyr-functions.html#计数函数"><i class="fa fa-check"></i><b>2.3.3</b> 计数函数</a></li>
<li class="chapter" data-level="2.3.4" data-path="dplyr-functions.html"><a href="dplyr-functions.html#排序函数"><i class="fa fa-check"></i><b>2.3.4</b> 排序函数</a></li>
<li class="chapter" data-level="2.3.5" data-path="dplyr-functions.html"><a href="dplyr-functions.html#提取向量"><i class="fa fa-check"></i><b>2.3.5</b> 提取向量</a></li>
<li class="chapter" data-level="2.3.6" data-path="dplyr-functions.html"><a href="dplyr-functions.html#dplyr:slice"><i class="fa fa-check"></i><b>2.3.6</b> slice 系列</a></li>
<li class="chapter" data-level="2.3.7" data-path="dplyr-functions.html"><a href="dplyr-functions.html#group-系列"><i class="fa fa-check"></i><b>2.3.7</b> group 系列</a></li>
<li class="chapter" data-level="2.3.8" data-path="dplyr-functions.html"><a href="dplyr-functions.html#其它函数"><i class="fa fa-check"></i><b>2.3.8</b> 其它函数</a></li>
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<li class="chapter" data-level="2.4" data-path="dplyr-merge-two-table.html"><a href="dplyr-merge-two-table.html"><i class="fa fa-check"></i><b>2.4</b> 表关联</a>
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<li class="chapter" data-level="2.4.1" data-path="dplyr-merge-two-table.html"><a href="dplyr-merge-two-table.html#dplyr:merge-table-usage"><i class="fa fa-check"></i><b>2.4.1</b> 两表关联</a></li>
<li class="chapter" data-level="2.4.2" data-path="dplyr-merge-two-table.html"><a href="dplyr-merge-two-table.html#dplyr:merge-multiple-table"><i class="fa fa-check"></i><b>2.4.2</b> 多表操作</a></li>
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<li class="chapter" data-level="2.5" data-path="dplyr-groupby-manipulation.html"><a href="dplyr-groupby-manipulation.html"><i class="fa fa-check"></i><b>2.5</b> 分组操作</a>
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<li class="chapter" data-level="2.5.1" data-path="dplyr-groupby-manipulation.html"><a href="dplyr-groupby-manipulation.html#添加分组"><i class="fa fa-check"></i><b>2.5.1</b> 添加分组</a></li>
<li class="chapter" data-level="2.5.2" data-path="dplyr-groupby-manipulation.html"><a href="dplyr-groupby-manipulation.html#查看分组"><i class="fa fa-check"></i><b>2.5.2</b> 查看分组</a></li>
<li class="chapter" data-level="2.5.3" data-path="dplyr-groupby-manipulation.html"><a href="dplyr-groupby-manipulation.html#更改和添加分组变量"><i class="fa fa-check"></i><b>2.5.3</b> 更改和添加分组变量</a></li>
<li class="chapter" data-level="2.5.4" data-path="dplyr-groupby-manipulation.html"><a href="dplyr-groupby-manipulation.html#删除分组变量"><i class="fa fa-check"></i><b>2.5.4</b> 删除分组变量</a></li>
<li class="chapter" data-level="2.5.5" data-path="dplyr-groupby-manipulation.html"><a href="dplyr-groupby-manipulation.html#动词影响"><i class="fa fa-check"></i><b>2.5.5</b> 动词影响</a></li>
</ul></li>
<li class="chapter" data-level="2.6" data-path="dplyr-column-manipulation.html"><a href="dplyr-column-manipulation.html"><i class="fa fa-check"></i><b>2.6</b> 列操作</a>
<ul>
<li class="chapter" data-level="2.6.1" data-path="dplyr-column-manipulation.html"><a href="dplyr-column-manipulation.html#dplyr-column-manipulation-basic-usage"><i class="fa fa-check"></i><b>2.6.1</b> 基础用法</a></li>
<li class="chapter" data-level="2.6.2" data-path="dplyr-column-manipulation.html"><a href="dplyr-column-manipulation.html#多种函数功能"><i class="fa fa-check"></i><b>2.6.2</b> 多种函数功能</a></li>
<li class="chapter" data-level="2.6.3" data-path="dplyr-column-manipulation.html"><a href="dplyr-column-manipulation.html#当前列"><i class="fa fa-check"></i><b>2.6.3</b> 当前列</a></li>
</ul></li>
<li class="chapter" data-level="2.7" data-path="dplyr-row-manipulation.html"><a href="dplyr-row-manipulation.html"><i class="fa fa-check"></i><b>2.7</b> 行操作</a>
<ul>
<li class="chapter" data-level="2.7.1" data-path="dplyr-row-manipulation.html"><a href="dplyr-row-manipulation.html#比较差异"><i class="fa fa-check"></i><b>2.7.1</b> 比较差异</a></li>
<li class="chapter" data-level="2.7.2" data-path="dplyr-row-manipulation.html"><a href="dplyr-row-manipulation.html#常用案例"><i class="fa fa-check"></i><b>2.7.2</b> 常用案例</a></li>
</ul></li>
<li class="chapter" data-level="2.8" data-path="dplyr-programming.html"><a href="dplyr-programming.html"><i class="fa fa-check"></i><b>2.8</b> <code>dplyr</code>编程</a>
<ul>
<li class="chapter" data-level="2.8.1" data-path="dplyr-programming.html"><a href="dplyr-programming.html#案例"><i class="fa fa-check"></i><b>2.8.1</b> 案例</a></li>
</ul></li>
<li class="chapter" data-level="2.9" data-path="dplyr-reference-material.html"><a href="dplyr-reference-material.html"><i class="fa fa-check"></i><b>2.9</b> 参考资料</a></li>
</ul></li>
<li class="chapter" data-level="3" data-path="Data-tidyr-package.html"><a href="Data-tidyr-package.html"><i class="fa fa-check"></i><b>3</b> 整洁数据之 tidyr</a>
<ul>
<li class="chapter" data-level="3.1" data-path="tidyr-useage.html"><a href="tidyr-useage.html"><i class="fa fa-check"></i><b>3.1</b> tidyr 介绍</a>
<ul>
<li class="chapter" data-level="3.1.1" data-path="tidyr-useage.html"><a href="tidyr-useage.html#tidyr:install"><i class="fa fa-check"></i><b>3.1.1</b> 安装</a></li>
<li class="chapter" data-level="3.1.2" data-path="tidyr-useage.html"><a href="tidyr-useage.html#tidyr:functions"><i class="fa fa-check"></i><b>3.1.2</b> 主要功能</a></li>
</ul></li>
<li class="chapter" data-level="3.2" data-path="pivoting.html"><a href="pivoting.html"><i class="fa fa-check"></i><b>3.2</b> 长宽转换</a>
<ul>
<li class="chapter" data-level="3.2.1" data-path="pivoting.html"><a href="pivoting.html#宽转长"><i class="fa fa-check"></i><b>3.2.1</b> 宽转长</a></li>
<li class="chapter" data-level="3.2.2" data-path="pivoting.html"><a href="pivoting.html#用法-1"><i class="fa fa-check"></i><b>3.2.2</b> 用法</a></li>
<li class="chapter" data-level="3.2.3" data-path="pivoting.html"><a href="pivoting.html#长转宽"><i class="fa fa-check"></i><b>3.2.3</b> 长转宽</a></li>
<li class="chapter" data-level="3.2.4" data-path="pivoting.html"><a href="pivoting.html#用法-2"><i class="fa fa-check"></i><b>3.2.4</b> 用法</a></li>
</ul></li>
<li class="chapter" data-level="3.3" data-path="tidyr-rectangle.html"><a href="tidyr-rectangle.html"><i class="fa fa-check"></i><b>3.3</b> 矩形数据</a></li>
<li class="chapter" data-level="3.4" data-path="tidyr-nest-data.html"><a href="tidyr-nest-data.html"><i class="fa fa-check"></i><b>3.4</b> 嵌套数据</a>
<ul>
<li class="chapter" data-level="3.4.1" data-path="tidyr-nest-data.html"><a href="tidyr-nest-data.html#基础"><i class="fa fa-check"></i><b>3.4.1</b> 基础</a></li>
<li class="chapter" data-level="3.4.2" data-path="tidyr-nest-data.html"><a href="tidyr-nest-data.html#嵌套数据和模型"><i class="fa fa-check"></i><b>3.4.2</b> 嵌套数据和模型</a></li>
</ul></li>
<li class="chapter" data-level="3.5" data-path="character-vector.html"><a href="character-vector.html"><i class="fa fa-check"></i><b>3.5</b> 字符处理</a>
<ul>
<li class="chapter" data-level="3.5.1" data-path="character-vector.html"><a href="character-vector.html#新列提取"><i class="fa fa-check"></i><b>3.5.1</b> 新列提取</a></li>
<li class="chapter" data-level="3.5.2" data-path="character-vector.html"><a href="character-vector.html#拆分"><i class="fa fa-check"></i><b>3.5.2</b> 拆分</a></li>
<li class="chapter" data-level="3.5.3" data-path="character-vector.html"><a href="character-vector.html#列拆分行"><i class="fa fa-check"></i><b>3.5.3</b> 列拆分行</a></li>
<li class="chapter" data-level="3.5.4" data-path="character-vector.html"><a href="character-vector.html#合并多列"><i class="fa fa-check"></i><b>3.5.4</b> 合并多列</a></li>
</ul></li>
<li class="chapter" data-level="3.6" data-path="tidyr-expand.html"><a href="tidyr-expand.html"><i class="fa fa-check"></i><b>3.6</b> 扩展数据框</a></li>
<li class="chapter" data-level="3.7" data-path="tidyr-fill-NA.html"><a href="tidyr-fill-NA.html"><i class="fa fa-check"></i><b>3.7</b> 缺失值</a>
<ul>
<li class="chapter" data-level="3.7.1" data-path="tidyr-fill-NA.html"><a href="tidyr-fill-NA.html#replace_na"><i class="fa fa-check"></i><b>3.7.1</b> replace_na</a></li>
<li class="chapter" data-level="3.7.2" data-path="tidyr-fill-NA.html"><a href="tidyr-fill-NA.html#fill"><i class="fa fa-check"></i><b>3.7.2</b> fill</a></li>
<li class="chapter" data-level="3.7.3" data-path="tidyr-fill-NA.html"><a href="tidyr-fill-NA.html#drop_na"><i class="fa fa-check"></i><b>3.7.3</b> drop_na</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="4" data-path="character-handling.html"><a href="character-handling.html"><i class="fa fa-check"></i><b>4</b> 字符处理</a>
<ul>
<li class="chapter" data-level="4.1" data-path="character-base-R.html"><a href="character-base-R.html"><i class="fa fa-check"></i><b>4.1</b> base R</a>
<ul>
<li class="chapter" data-level="4.1.1" data-path="character-base-R.html"><a href="character-base-R.html#单双引号"><i class="fa fa-check"></i><b>4.1.1</b> 单双引号</a></li>
<li class="chapter" data-level="4.1.2" data-path="character-base-R.html"><a href="character-base-R.html#转义"><i class="fa fa-check"></i><b>4.1.2</b> 转义</a></li>
<li class="chapter" data-level="4.1.3" data-path="character-base-R.html"><a href="character-base-R.html#常用函数"><i class="fa fa-check"></i><b>4.1.3</b> 常用函数</a></li>
<li class="chapter" data-level="4.1.4" data-path="character-base-R.html"><a href="character-base-R.html#newfeatures"><i class="fa fa-check"></i><b>4.1.4</b> 新特性</a></li>
</ul></li>
<li class="chapter" data-level="4.2" data-path="character-stringr-packages.html"><a href="character-stringr-packages.html"><i class="fa fa-check"></i><b>4.2</b> stringr</a>
<ul>
<li class="chapter" data-level="4.2.1" data-path="character-stringr-packages.html"><a href="character-stringr-packages.html#stringr-install"><i class="fa fa-check"></i><b>4.2.1</b> 安装</a></li>
<li class="chapter" data-level="4.2.2" data-path="character-stringr-packages.html"><a href="character-stringr-packages.html#stringr-usage"><i class="fa fa-check"></i><b>4.2.2</b> 基本使用</a></li>
<li class="chapter" data-level="4.2.3" data-path="character-stringr-packages.html"><a href="character-stringr-packages.html#stringr-functions"><i class="fa fa-check"></i><b>4.2.3</b> 常用函数</a></li>
</ul></li>
<li class="chapter" data-level="4.3" data-path="character-application.html"><a href="character-application.html"><i class="fa fa-check"></i><b>4.3</b> 综合运用</a>
<ul>
<li class="chapter" data-level="4.3.1" data-path="character-application.html"><a href="character-application.html#实现excel函数"><i class="fa fa-check"></i><b>4.3.1</b> 实现excel函数</a></li>
<li class="chapter" data-level="4.3.2" data-path="character-application.html"><a href="character-application.html#使用案例"><i class="fa fa-check"></i><b>4.3.2</b> 使用案例</a></li>
</ul></li>
<li class="chapter" data-level="4.4" data-path="character-the-difference-stringr-and-base.html"><a href="character-the-difference-stringr-and-base.html"><i class="fa fa-check"></i><b>4.4</b> base 和 stringr</a></li>
<li class="chapter" data-level="4.5" data-path="character-reference-material.html"><a href="character-reference-material.html"><i class="fa fa-check"></i><b>4.5</b> 参考资料</a></li>
</ul></li>
<li class="chapter" data-level="5" data-path="datetime.html"><a href="datetime.html"><i class="fa fa-check"></i><b>5</b> 时间处理</a>
<ul>
<li class="chapter" data-level="5.1" data-path="datetime-base-R.html"><a href="datetime-base-R.html"><i class="fa fa-check"></i><b>5.1</b> base R</a>
<ul>
<li class="chapter" data-level="5.1.1" data-path="datetime-base-R.html"><a href="datetime-base-R.html#the-date-class"><i class="fa fa-check"></i><b>5.1.1</b> Date</a></li>
<li class="chapter" data-level="5.1.2" data-path="datetime-base-R.html"><a href="datetime-base-R.html#the-POSIXct-class"><i class="fa fa-check"></i><b>5.1.2</b> POSIXct</a></li>
<li class="chapter" data-level="5.1.3" data-path="datetime-base-R.html"><a href="datetime-base-R.html#the-POSIXlt-class"><i class="fa fa-check"></i><b>5.1.3</b> POSIXlt</a></li>
</ul></li>
<li class="chapter" data-level="5.2" data-path="lubridate.html"><a href="lubridate.html"><i class="fa fa-check"></i><b>5.2</b> lubridate</a>
<ul>
<li class="chapter" data-level="5.2.1" data-path="lubridate.html"><a href="lubridate.html#lubridate-install"><i class="fa fa-check"></i><b>5.2.1</b> 安装包</a></li>
<li class="chapter" data-level="5.2.2" data-path="lubridate.html"><a href="lubridate.html#get-current-datetime"><i class="fa fa-check"></i><b>5.2.2</b> 当前时间日期</a></li>
<li class="chapter" data-level="5.2.3" data-path="lubridate.html"><a href="lubridate.html#make-datetime"><i class="fa fa-check"></i><b>5.2.3</b> 构造日期时间</a></li>
<li class="chapter" data-level="5.2.4" data-path="lubridate.html"><a href="lubridate.html#parse-datetime"><i class="fa fa-check"></i><b>5.2.4</b> 解析日期时间</a></li>
<li class="chapter" data-level="5.2.5" data-path="lubridate.html"><a href="lubridate.html#extracting-datetime-information"><i class="fa fa-check"></i><b>5.2.5</b> 提取日期时间成分</a></li>
<li class="chapter" data-level="5.2.6" data-path="lubridate.html"><a href="lubridate.html#time-zones"><i class="fa fa-check"></i><b>5.2.6</b> 处理时区</a></li>
<li class="chapter" data-level="5.2.7" data-path="lubridate.html"><a href="lubridate.html#interveal"><i class="fa fa-check"></i><b>5.2.7</b> 时间间隔</a></li>
<li class="chapter" data-level="5.2.8" data-path="lubridate.html"><a href="lubridate.html#calculate-datetime"><i class="fa fa-check"></i><b>5.2.8</b> 时间日期计算</a></li>
</ul></li>
<li class="chapter" data-level="5.3" data-path="datetime-application.html"><a href="datetime-application.html"><i class="fa fa-check"></i><b>5.3</b> 综合运用</a>
<ul>
<li class="chapter" data-level="5.3.1" data-path="datetime-application.html"><a href="datetime-application.html#日报同环比计算"><i class="fa fa-check"></i><b>5.3.1</b> 日报同环比计算</a></li>
<li class="chapter" data-level="5.3.2" data-path="datetime-application.html"><a href="datetime-application.html#清洗不同类型日期格式"><i class="fa fa-check"></i><b>5.3.2</b> 清洗不同类型日期格式</a></li>
<li class="chapter" data-level="5.3.3" data-path="datetime-application.html"><a href="datetime-application.html#扫码后中奖时间匹配"><i class="fa fa-check"></i><b>5.3.3</b> 扫码后中奖时间匹配</a></li>
</ul></li>
<li class="chapter" data-level="5.4" data-path="datetime-additional-information.html"><a href="datetime-additional-information.html"><i class="fa fa-check"></i><b>5.4</b> 补充资料</a>
<ul>
<li class="chapter" data-level="5.4.1" data-path="datetime-additional-information.html"><a href="datetime-additional-information.html#excel-and-r"><i class="fa fa-check"></i><b>5.4.1</b> Excel and R</a></li>
<li class="chapter" data-level="5.4.2" data-path="datetime-additional-information.html"><a href="datetime-additional-information.html#参考资料-1"><i class="fa fa-check"></i><b>5.4.2</b> 参考资料</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="6" data-path="forcats.html"><a href="forcats.html"><i class="fa fa-check"></i><b>6</b> 因子介绍</a>
<ul>
<li class="chapter" data-level="6.1" data-path="forcats-introduction.html"><a href="forcats-introduction.html"><i class="fa fa-check"></i><b>6.1</b> 介绍</a>
<ul>
<li class="chapter" data-level="6.1.1" data-path="forcats-introduction.html"><a href="forcats-introduction.html#forcats:install"><i class="fa fa-check"></i><b>6.1.1</b> 安装</a></li>
</ul></li>
<li class="chapter" data-level="6.2" data-path="forcats-usage.html"><a href="forcats-usage.html"><i class="fa fa-check"></i><b>6.2</b> 用法</a>
<ul>
<li class="chapter" data-level="6.2.1" data-path="forcats-usage.html"><a href="forcats-usage.html#创建因子"><i class="fa fa-check"></i><b>6.2.1</b> 创建因子</a></li>
<li class="chapter" data-level="6.2.2" data-path="forcats-usage.html"><a href="forcats-usage.html#修改因子顺序"><i class="fa fa-check"></i><b>6.2.2</b> 修改因子顺序</a></li>
<li class="chapter" data-level="6.2.3" data-path="forcats-usage.html"><a href="forcats-usage.html#修改因子级别"><i class="fa fa-check"></i><b>6.2.3</b> 修改因子级别</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="7" data-path="Data-Manipulation-datatable.html"><a href="Data-Manipulation-datatable.html"><i class="fa fa-check"></i><b>7</b> data.table</a>
<ul>
<li class="chapter" data-level="7.1" data-path="datatable-description.html"><a href="datatable-description.html"><i class="fa fa-check"></i><b>7.1</b> 基础介绍</a>
<ul>
<li class="chapter" data-level="7.1.1" data-path="datatable-description.html"><a href="datatable-description.html#读取数据"><i class="fa fa-check"></i><b>7.1.1</b> 读取数据</a></li>
<li class="chapter" data-level="7.1.2" data-path="datatable-description.html"><a href="datatable-description.html#基本格式"><i class="fa fa-check"></i><b>7.1.2</b> 基本格式</a></li>
<li class="chapter" data-level="7.1.3" data-path="datatable-description.html"><a href="datatable-description.html#i-j-by-使用"><i class="fa fa-check"></i><b>7.1.3</b> i j by 使用</a></li>
<li class="chapter" data-level="7.1.4" data-path="datatable-description.html"><a href="datatable-description.html#行列筛选总结"><i class="fa fa-check"></i><b>7.1.4</b> 行列筛选总结</a></li>
</ul></li>
<li class="chapter" data-level="7.2" data-path="datatable-usage.html"><a href="datatable-usage.html"><i class="fa fa-check"></i><b>7.2</b> 常规操作</a>
<ul>
<li class="chapter" data-level="7.2.1" data-path="datatable-usage.html"><a href="datatable-usage.html#行筛选"><i class="fa fa-check"></i><b>7.2.1</b> 行筛选</a></li>
<li class="chapter" data-level="7.2.2" data-path="datatable-usage.html"><a href="datatable-usage.html#新增更新列"><i class="fa fa-check"></i><b>7.2.2</b> 新增更新列</a></li>
<li class="chapter" data-level="7.2.3" data-path="datatable-usage.html"><a href="datatable-usage.html#排序"><i class="fa fa-check"></i><b>7.2.3</b> 排序</a></li>
</ul></li>
<li class="chapter" data-level="7.3" data-path="datatable-function.html"><a href="datatable-function.html"><i class="fa fa-check"></i><b>7.3</b> 常用函数</a>
<ul>
<li class="chapter" data-level="7.3.1" data-path="datatable-function.html"><a href="datatable-function.html#特殊符号"><i class="fa fa-check"></i><b>7.3.1</b> 特殊符号</a></li>
<li class="chapter" data-level="7.3.2" data-path="datatable-function.html"><a href="datatable-function.html#排序函数-1"><i class="fa fa-check"></i><b>7.3.2</b> 排序函数</a></li>
<li class="chapter" data-level="7.3.3" data-path="datatable-function.html"><a href="datatable-function.html#非重复计数"><i class="fa fa-check"></i><b>7.3.3</b> 非重复计数</a></li>
<li class="chapter" data-level="7.3.4" data-path="datatable-function.html"><a href="datatable-function.html#判断函数"><i class="fa fa-check"></i><b>7.3.4</b> 判断函数</a></li>
<li class="chapter" data-level="7.3.5" data-path="datatable-function.html"><a href="datatable-function.html#交集-差集-合并"><i class="fa fa-check"></i><b>7.3.5</b> 交集 差集 合并</a></li>
<li class="chapter" data-level="7.3.6" data-path="datatable-function.html"><a href="datatable-function.html#长宽转换"><i class="fa fa-check"></i><b>7.3.6</b> 长宽转换</a></li>
<li class="chapter" data-level="7.3.7" data-path="datatable-function.html"><a href="datatable-function.html#表连接"><i class="fa fa-check"></i><b>7.3.7</b> 表连接</a></li>
</ul></li>
<li class="chapter" data-level="7.4" data-path="datatable-advanced-functions.html"><a href="datatable-advanced-functions.html"><i class="fa fa-check"></i><b>7.4</b> 高级函数</a>
<ul>
<li class="chapter" data-level="7.4.1" data-path="datatable-advanced-functions.html"><a href="datatable-advanced-functions.html#groupingsets"><i class="fa fa-check"></i><b>7.4.1</b> groupingsets</a></li>
<li class="chapter" data-level="7.4.2" data-path="datatable-advanced-functions.html"><a href="datatable-advanced-functions.html#rleid"><i class="fa fa-check"></i><b>7.4.2</b> rleid</a></li>
<li class="chapter" data-level="7.4.3" data-path="datatable-advanced-functions.html"><a href="datatable-advanced-functions.html#shift"><i class="fa fa-check"></i><b>7.4.3</b> shift</a></li>
<li class="chapter" data-level="7.4.4" data-path="datatable-advanced-functions.html"><a href="datatable-advanced-functions.html#j"><i class="fa fa-check"></i><b>7.4.4</b> J</a></li>
</ul></li>
<li class="chapter" data-level="7.5" data-path="datatable-tips.html"><a href="datatable-tips.html"><i class="fa fa-check"></i><b>7.5</b> 小技巧</a>
<ul>
<li class="chapter" data-level="7.5.1" data-path="datatable-tips.html"><a href="datatable-tips.html#用抑制中间过程输出"><i class="fa fa-check"></i><b>7.5.1</b> 用{}抑制中间过程输出</a></li>
<li class="chapter" data-level="7.5.2" data-path="datatable-tips.html"><a href="datatable-tips.html#使用打印data.table"><i class="fa fa-check"></i><b>7.5.2</b> 使用[]打印data.table</a></li>
</ul></li>
<li class="chapter" data-level="7.6" data-path="datatable-application.html"><a href="datatable-application.html"><i class="fa fa-check"></i><b>7.6</b> 运用</a>
<ul>
<li class="chapter" data-level="7.6.1" data-path="datatable-application.html"><a href="datatable-application.html#自定义函数计算"><i class="fa fa-check"></i><b>7.6.1</b> 自定义函数计算</a></li>
<li class="chapter" data-level="7.6.2" data-path="datatable-application.html"><a href="datatable-application.html#带汇总的聚合运算"><i class="fa fa-check"></i><b>7.6.2</b> 带汇总的聚合运算</a></li>
<li class="chapter" data-level="7.6.3" data-path="datatable-application.html"><a href="datatable-application.html#行列转变"><i class="fa fa-check"></i><b>7.6.3</b> 行列转变</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="8" data-path="database.html"><a href="database.html"><i class="fa fa-check"></i><b>8</b> database</a>
<ul>
<li class="chapter" data-level="8.1" data-path="database-install.html"><a href="database-install.html"><i class="fa fa-check"></i><b>8.1</b> 安装数据库</a></li>
<li class="chapter" data-level="8.2" data-path="database-odbc-package.html"><a href="database-odbc-package.html"><i class="fa fa-check"></i><b>8.2</b> odbc包</a>
<ul>
<li class="chapter" data-level="8.2.1" data-path="database-odbc-package.html"><a href="database-odbc-package.html#安装包"><i class="fa fa-check"></i><b>8.2.1</b> 安装包</a></li>
<li class="chapter" data-level="8.2.2" data-path="database-odbc-package.html"><a href="database-odbc-package.html#驱动安装"><i class="fa fa-check"></i><b>8.2.2</b> 驱动安装</a></li>
<li class="chapter" data-level="8.2.3" data-path="database-odbc-package.html"><a href="database-odbc-package.html#连接数据库"><i class="fa fa-check"></i><b>8.2.3</b> 连接数据库</a></li>
<li class="chapter" data-level="8.2.4" data-path="database-odbc-package.html"><a href="database-odbc-package.html#读写数据库"><i class="fa fa-check"></i><b>8.2.4</b> 读写数据库</a></li>
</ul></li>
<li class="chapter" data-level="8.3" data-path="database-DBI-package.html"><a href="database-DBI-package.html"><i class="fa fa-check"></i><b>8.3</b> DBI包</a>
<ul>
<li class="chapter" data-level="8.3.1" data-path="database-DBI-package.html"><a href="database-DBI-package.html#安装-1"><i class="fa fa-check"></i><b>8.3.1</b> 安装</a></li>
<li class="chapter" data-level="8.3.2" data-path="database-DBI-package.html"><a href="database-DBI-package.html#连接数据库-1"><i class="fa fa-check"></i><b>8.3.2</b> 连接数据库</a></li>
<li class="chapter" data-level="8.3.3" data-path="database-DBI-package.html"><a href="database-DBI-package.html#读写数据库-1"><i class="fa fa-check"></i><b>8.3.3</b> 读写数据库</a></li>
<li class="chapter" data-level="8.3.4" data-path="database-DBI-package.html"><a href="database-DBI-package.html#其它函数介绍"><i class="fa fa-check"></i><b>8.3.4</b> 其它函数介绍</a></li>
</ul></li>
<li class="chapter" data-level="8.4" data-path="database-else-package.html"><a href="database-else-package.html"><i class="fa fa-check"></i><b>8.4</b> 其他R包</a>
<ul>
<li class="chapter" data-level="8.4.1" data-path="database-else-package.html"><a href="database-else-package.html#rodbc包"><i class="fa fa-check"></i><b>8.4.1</b> RODBC包</a></li>
<li class="chapter" data-level="8.4.2" data-path="database-else-package.html"><a href="database-else-package.html#roracle包"><i class="fa fa-check"></i><b>8.4.2</b> ROracle包</a></li>
<li class="chapter" data-level="8.4.3" data-path="database-else-package.html"><a href="database-else-package.html#rmysql包"><i class="fa fa-check"></i><b>8.4.3</b> RMySQL包</a></li>
<li class="chapter" data-level="8.4.4" data-path="database-else-package.html"><a href="database-else-package.html#rsqlite"><i class="fa fa-check"></i><b>8.4.4</b> RSQLite</a></li>
</ul></li>
<li class="chapter" data-level="8.5" data-path="database-big-data.html"><a href="database-big-data.html"><i class="fa fa-check"></i><b>8.5</b> 大数据相关R包</a>
<ul>
<li class="chapter" data-level="8.5.1" data-path="database-big-data.html"><a href="database-big-data.html#sparklyr"><i class="fa fa-check"></i><b>8.5.1</b> sparklyr</a></li>
<li class="chapter" data-level="8.5.2" data-path="database-big-data.html"><a href="database-big-data.html#RClickhouse"><i class="fa fa-check"></i><b>8.5.2</b> RClickhouse</a></li>
</ul></li>
<li class="chapter" data-level="8.6" data-path="database-FAQ.html"><a href="database-FAQ.html"><i class="fa fa-check"></i><b>8.6</b> 常见问题</a>
<ul>
<li class="chapter" data-level="8.6.1" data-path="database-FAQ.html"><a href="database-FAQ.html#乱码问题"><i class="fa fa-check"></i><b>8.6.1</b> 乱码问题</a></li>
<li class="chapter" data-level="8.6.2" data-path="database-FAQ.html"><a href="database-FAQ.html#无法连接问题"><i class="fa fa-check"></i><b>8.6.2</b> 无法连接问题</a></li>
<li class="chapter" data-level="8.6.3" data-path="database-FAQ.html"><a href="database-FAQ.html#远程连接"><i class="fa fa-check"></i><b>8.6.3</b> 远程连接</a></li>
<li class="chapter" data-level="8.6.4" data-path="database-FAQ.html"><a href="database-FAQ.html#跳板机连接"><i class="fa fa-check"></i><b>8.6.4</b> 跳板机连接</a></li>
</ul></li>
<li class="chapter" data-level="8.7" data-path="database-dbplyr-package.html"><a href="database-dbplyr-package.html"><i class="fa fa-check"></i><b>8.7</b> dbplyr</a>
<ul>
<li class="chapter" data-level="8.7.1" data-path="database-dbplyr-package.html"><a href="database-dbplyr-package.html#安装-2"><i class="fa fa-check"></i><b>8.7.1</b> 安装</a></li>
<li class="chapter" data-level="8.7.2" data-path="database-dbplyr-package.html"><a href="database-dbplyr-package.html#基础用法-1"><i class="fa fa-check"></i><b>8.7.2</b> 基础用法</a></li>
<li class="chapter" data-level="8.7.3" data-path="database-dbplyr-package.html"><a href="database-dbplyr-package.html#无法正确转化"><i class="fa fa-check"></i><b>8.7.3</b> 无法正确转化</a></li>
</ul></li>
<li class="chapter" data-level="8.8" data-path="database-reference-material.html"><a href="database-reference-material.html"><i class="fa fa-check"></i><b>8.8</b> 参考资料</a></li>
</ul></li>
<li class="chapter" data-level="9" data-path="R-loop-structure.html"><a href="R-loop-structure.html"><i class="fa fa-check"></i><b>9</b> 循环结构</a>
<ul>
<li class="chapter" data-level="9.1" data-path="R-loop-description.html"><a href="R-loop-description.html"><i class="fa fa-check"></i><b>9.1</b> R循环介绍</a>
<ul>
<li class="chapter" data-level="9.1.1" data-path="R-loop-description.html"><a href="R-loop-description.html#R:loop-example"><i class="fa fa-check"></i><b>9.1.1</b> 简单示例</a></li>
<li class="chapter" data-level="9.1.2" data-path="R-loop-description.html"><a href="R-loop-description.html#three:loop-structure"><i class="fa fa-check"></i><b>9.1.2</b> 循环结构</a></li>
<li class="chapter" data-level="9.1.3" data-path="R-loop-description.html"><a href="R-loop-description.html#loop:control"><i class="fa fa-check"></i><b>9.1.3</b> 循环控制</a></li>
<li class="chapter" data-level="9.1.4" data-path="R-loop-description.html"><a href="R-loop-description.html#嵌套循环"><i class="fa fa-check"></i><b>9.1.4</b> 嵌套循环</a></li>
</ul></li>
<li class="chapter" data-level="9.2" data-path="loop-changes.html"><a href="loop-changes.html"><i class="fa fa-check"></i><b>9.2</b> 循环变化</a>
<ul>
<li class="chapter" data-level="9.2.1" data-path="loop-changes.html"><a href="loop-changes.html#修改已有对象"><i class="fa fa-check"></i><b>9.2.1</b> 修改已有对象</a></li>
<li class="chapter" data-level="9.2.2" data-path="loop-changes.html"><a href="loop-changes.html#循环模式"><i class="fa fa-check"></i><b>9.2.2</b> 循环模式</a></li>
<li class="chapter" data-level="9.2.3" data-path="loop-changes.html"><a href="loop-changes.html#未知长度输出"><i class="fa fa-check"></i><b>9.2.3</b> 未知长度输出</a></li>
</ul></li>
<li class="chapter" data-level="9.3" data-path="apply-function.html"><a href="apply-function.html"><i class="fa fa-check"></i><b>9.3</b> apply系列函数</a>
<ul>
<li class="chapter" data-level="9.3.1" data-path="apply-function.html"><a href="apply-function.html#lapply"><i class="fa fa-check"></i><b>9.3.1</b> lapply 循环迭代</a></li>
<li class="chapter" data-level="9.3.2" data-path="apply-function.html"><a href="apply-function.html#sapply"><i class="fa fa-check"></i><b>9.3.2</b> sapply</a></li>
<li class="chapter" data-level="9.3.3" data-path="apply-function.html"><a href="apply-function.html#vapply"><i class="fa fa-check"></i><b>9.3.3</b> vapply 迭代安全函数</a></li>
<li class="chapter" data-level="9.3.4" data-path="apply-function.html"><a href="apply-function.html#apply"><i class="fa fa-check"></i><b>9.3.4</b> apply 多维数据</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="10" data-path="purrr-Iteration.html"><a href="purrr-Iteration.html"><i class="fa fa-check"></i><b>10</b> 循环迭代purrr介绍</a>
<ul>
<li class="chapter" data-level="10.1" data-path="安装-3.html"><a href="安装-3.html"><i class="fa fa-check"></i><b>10.1</b> 安装</a></li>
<li class="chapter" data-level="10.2" data-path="purrr-basic-usage.html"><a href="purrr-basic-usage.html"><i class="fa fa-check"></i><b>10.2</b> 常规用法</a>
<ul>
<li class="chapter" data-level="10.2.1" data-path="purrr-basic-usage.html"><a href="purrr-basic-usage.html#map-系列"><i class="fa fa-check"></i><b>10.2.1</b> map 系列</a></li>
<li class="chapter" data-level="10.2.2" data-path="purrr-basic-usage.html"><a href="purrr-basic-usage.html#pmap-系列"><i class="fa fa-check"></i><b>10.2.2</b> pmap 系列</a></li>
</ul></li>
<li class="chapter" data-level="10.3" data-path="purrr-map.html"><a href="purrr-map.html"><i class="fa fa-check"></i><b>10.3</b> map系列函数</a>
<ul>
<li class="chapter" data-level="10.3.1" data-path="purrr-map.html"><a href="purrr-map.html#用法-3"><i class="fa fa-check"></i><b>10.3.1</b> 用法</a></li>
<li class="chapter" data-level="10.3.2" data-path="purrr-map.html"><a href="purrr-map.html#案例-5"><i class="fa fa-check"></i><b>10.3.2</b> 案例</a></li>
</ul></li>
<li class="chapter" data-level="10.4" data-path="purrr-map2.html"><a href="purrr-map2.html"><i class="fa fa-check"></i><b>10.4</b> map2 系列函数</a></li>
<li class="chapter" data-level="10.5" data-path="purrr-multi-parameter.html"><a href="purrr-multi-parameter.html"><i class="fa fa-check"></i><b>10.5</b> pmap系列函数</a></li>
<li class="chapter" data-level="10.6" data-path="purrr-reduce.html"><a href="purrr-reduce.html"><i class="fa fa-check"></i><b>10.6</b> 归约累计函数</a>
<ul>
<li class="chapter" data-level="10.6.1" data-path="purrr-reduce.html"><a href="purrr-reduce.html#reduce-函数"><i class="fa fa-check"></i><b>10.6.1</b> reduce 函数</a></li>
<li class="chapter" data-level="10.6.2" data-path="purrr-reduce.html"><a href="purrr-reduce.html#accumulate-函数"><i class="fa fa-check"></i><b>10.6.2</b> accumulate 函数</a></li>
</ul></li>
<li class="chapter" data-level="10.7" data-path="purrr-safely-functions.html"><a href="purrr-safely-functions.html"><i class="fa fa-check"></i><b>10.7</b> 安全函数</a></li>
<li class="chapter" data-level="10.8" data-path="purrr-else-functions.html"><a href="purrr-else-functions.html"><i class="fa fa-check"></i><b>10.8</b> 其他函数介绍</a>
<ul>
<li class="chapter" data-level="10.8.1" data-path="purrr-else-functions.html"><a href="purrr-else-functions.html#flatten-系列"><i class="fa fa-check"></i><b>10.8.1</b> flatten 系列</a></li>
<li class="chapter" data-level="10.8.2" data-path="purrr-else-functions.html"><a href="purrr-else-functions.html#imap-函数"><i class="fa fa-check"></i><b>10.8.2</b> imap 函数</a></li>
<li class="chapter" data-level="10.8.3" data-path="purrr-else-functions.html"><a href="purrr-else-functions.html#walk-系列"><i class="fa fa-check"></i><b>10.8.3</b> walk 系列</a></li>
<li class="chapter" data-level="10.8.4" data-path="purrr-else-functions.html"><a href="purrr-else-functions.html#逻辑判断函数"><i class="fa fa-check"></i><b>10.8.4</b> 逻辑判断函数</a></li>
<li class="chapter" data-level="10.8.5" data-path="purrr-else-functions.html"><a href="purrr-else-functions.html#提取函数"><i class="fa fa-check"></i><b>10.8.5</b> 提取函数</a></li>
<li class="chapter" data-level="10.8.6" data-path="purrr-else-functions.html"><a href="purrr-else-functions.html#筛选函数"><i class="fa fa-check"></i><b>10.8.6</b> 筛选函数</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="11" data-path="self-define-function.html"><a href="self-define-function.html"><i class="fa fa-check"></i><b>11</b> 自定义函数</a>
<ul>
<li class="chapter" data-level="11.1" data-path="define-function-example.html"><a href="define-function-example.html"><i class="fa fa-check"></i><b>11.1</b> 简单示例</a></li>
<li class="chapter" data-level="11.2" data-path="define-function-conditional-execution.html"><a href="define-function-conditional-execution.html"><i class="fa fa-check"></i><b>11.2</b> 条件执行</a>
<ul>
<li class="chapter" data-level="11.2.1" data-path="define-function-conditional-execution.html"><a href="define-function-conditional-execution.html#多条件执行"><i class="fa fa-check"></i><b>11.2.1</b> 多条件执行</a></li>
</ul></li>
<li class="chapter" data-level="11.3" data-path="define-function-parameter.html"><a href="define-function-parameter.html"><i class="fa fa-check"></i><b>11.3</b> 函数参数</a>
<ul>
<li class="chapter" data-level="11.3.1" data-path="define-function-parameter.html"><a href="define-function-parameter.html#参数名称"><i class="fa fa-check"></i><b>11.3.1</b> 参数名称</a></li>
<li class="chapter" data-level="11.3.2" data-path="define-function-parameter.html"><a href="define-function-parameter.html#检查参数值"><i class="fa fa-check"></i><b>11.3.2</b> 检查参数值</a></li>
<li class="chapter" data-level="11.3.3" data-path="define-function-parameter.html"><a href="define-function-parameter.html#参数-5"><i class="fa fa-check"></i><b>11.3.3</b> …参数</a></li>
</ul></li>
<li class="chapter" data-level="11.4" data-path="function-return.html"><a href="function-return.html"><i class="fa fa-check"></i><b>11.4</b> 返回值</a>
<ul>
<li class="chapter" data-level="11.4.1" data-path="function-return.html"><a href="function-return.html#显式返回"><i class="fa fa-check"></i><b>11.4.1</b> 显式返回</a></li>
<li class="chapter" data-level="11.4.2" data-path="function-return.html"><a href="function-return.html#编写管道函数"><i class="fa fa-check"></i><b>11.4.2</b> 编写管道函数</a></li>
</ul></li>
<li class="chapter" data-level="11.5" data-path="function-environment.html"><a href="function-environment.html"><i class="fa fa-check"></i><b>11.5</b> 环境</a></li>
<li class="chapter" data-level="11.6" data-path="function-expand.html"><a href="function-expand.html"><i class="fa fa-check"></i><b>11.6</b> 拓展部分</a></li>
</ul></li>
<li class="chapter" data-level="12" data-path="file-system-operation.html"><a href="file-system-operation.html"><i class="fa fa-check"></i><b>12</b> R语言文件系统操作</a>
<ul>
<li class="chapter" data-level="12.1" data-path="file-base-r.html"><a href="file-base-r.html"><i class="fa fa-check"></i><b>12.1</b> base R</a>
<ul>
<li class="chapter" data-level="12.1.1" data-path="file-base-r.html"><a href="file-base-r.html#base:r-usage"><i class="fa fa-check"></i><b>12.1.1</b> 用法</a></li>
</ul></li>
<li class="chapter" data-level="12.2" data-path="fs-package.html"><a href="fs-package.html"><i class="fa fa-check"></i><b>12.2</b> fs package</a>
<ul>
<li class="chapter" data-level="12.2.1" data-path="fs-package.html"><a href="fs-package.html#fs-install"><i class="fa fa-check"></i><b>12.2.1</b> 安装</a></li>
<li class="chapter" data-level="12.2.2" data-path="fs-package.html"><a href="fs-package.html#fs-advanced"><i class="fa fa-check"></i><b>12.2.2</b> 优势</a></li>
<li class="chapter" data-level="12.2.3" data-path="fs-package.html"><a href="fs-package.html#fs-usage"><i class="fa fa-check"></i><b>12.2.3</b> 基础用法</a></li>
</ul></li>
<li class="chapter" data-level="12.3" data-path="fs-functions.html"><a href="fs-functions.html"><i class="fa fa-check"></i><b>12.3</b> fs函数介绍</a>
<ul>
<li class="chapter" data-level="12.3.1" data-path="fs-functions.html"><a href="fs-functions.html#fs-file-manipulation"><i class="fa fa-check"></i><b>12.3.1</b> 文件操作</a></li>
<li class="chapter" data-level="12.3.2" data-path="fs-functions.html"><a href="fs-functions.html#fs-dir-manipulation"><i class="fa fa-check"></i><b>12.3.2</b> 目录操作</a></li>
<li class="chapter" data-level="12.3.3" data-path="fs-functions.html"><a href="fs-functions.html#fs-link-manipulation"><i class="fa fa-check"></i><b>12.3.3</b> 链接操作</a></li>
<li class="chapter" data-level="12.3.4" data-path="fs-functions.html"><a href="fs-functions.html#fs-path-manipulation"><i class="fa fa-check"></i><b>12.3.4</b> 路径操作</a></li>
<li class="chapter" data-level="12.3.5" data-path="fs-functions.html"><a href="fs-functions.html#fs-help-manipulation"><i class="fa fa-check"></i><b>12.3.5</b> 辅助函数</a></li>
</ul></li>
<li class="chapter" data-level="12.4" data-path="file-base-fs-difference.html"><a href="file-base-fs-difference.html"><i class="fa fa-check"></i><b>12.4</b> base-fs-shell比较</a></li>
<li class="chapter" data-level="12.5" data-path="file-manipulation-reference-material.html"><a href="file-manipulation-reference-material.html"><i class="fa fa-check"></i><b>12.5</b> 参考资料</a></li>
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<li><a href="https://gitee.com/zhongyufei/Rbook" target="blank">gitee地址</a></li>

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<div id="datatable:description" class="section level2" number="7.1">
<h2><span class="header-section-number">7.1</span> 基础介绍</h2>
<p>本部分从data.table安装，内置的案例查看，到data.table的句式语法，实现基础行列筛选和聚合计算。</p>
<p>1.安装</p>
<p>安装详细信息请参考<a href="https://github.com/Rdatatable/data.table/wiki/Installation">the Installation wiki</a>，有关于不同系统安装首次以及相关说明。</p>
<div class="sourceCode" id="cb387"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb387-1"><a href="datatable-description.html#cb387-1" aria-hidden="true" tabindex="-1"></a><span class="fu">install.packages</span>(<span class="st">&quot;data.table&quot;</span>)</span>
<span id="cb387-2"><a href="datatable-description.html#cb387-2" aria-hidden="true" tabindex="-1"></a><span class="co"># latest development version:</span></span>
<span id="cb387-3"><a href="datatable-description.html#cb387-3" aria-hidden="true" tabindex="-1"></a>data.table<span class="sc">::</span><span class="fu">update.dev.pkg</span>()</span></code></pre></div>
<p>2.使用说明</p>
<p>通过以下代码查看内置的使用案例。</p>
<div class="sourceCode" id="cb388"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb388-1"><a href="datatable-description.html#cb388-1" aria-hidden="true" tabindex="-1"></a><span class="fu">library</span>(data.table)</span>
<span id="cb388-2"><a href="datatable-description.html#cb388-2" aria-hidden="true" tabindex="-1"></a><span class="fu">example</span>(data.table)</span></code></pre></div>
<div id="读取数据" class="section level3" number="7.1.1">
<h3><span class="header-section-number">7.1.1</span> 读取数据</h3>
<p>在我实际工作中接触的数据大部分以数据库,csv,Excel等形式存在，并且CSV格式数据较少。但是data.table包读取数据的<code>fread</code>函数仅接受CSV格式。如果是Excel格式文件，需要通过如<code>readxl</code>，<code>openxlsx</code>等包读入后转换为<code>data.table</code>格式数据。</p>
<p>fread 函数可以直接读取CSV格式文件,无论是本地文件或者在线文件,如下所示:</p>
<blockquote>
<p>案例中使用的数据集是R包<code>nycflights13</code>带的flights数据集。</p>
</blockquote>
<div class="sourceCode" id="cb389"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb389-1"><a href="datatable-description.html#cb389-1" aria-hidden="true" tabindex="-1"></a><span class="fu">library</span>(data.table)</span>
<span id="cb389-2"><a href="datatable-description.html#cb389-2" aria-hidden="true" tabindex="-1"></a>input <span class="ot">&lt;-</span> <span class="cf">if</span> (<span class="fu">file.exists</span>(<span class="st">&quot;./data/flights.csv&quot;</span>)) {</span>
<span id="cb389-3"><a href="datatable-description.html#cb389-3" aria-hidden="true" tabindex="-1"></a>   <span class="st">&quot;./data/flights.csv&quot;</span> <span class="co">#本地文件</span></span>
<span id="cb389-4"><a href="datatable-description.html#cb389-4" aria-hidden="true" tabindex="-1"></a>} <span class="cf">else</span> {</span>
<span id="cb389-5"><a href="datatable-description.html#cb389-5" aria-hidden="true" tabindex="-1"></a>  <span class="st">&quot;https://raw.githubusercontent.com/Rdatatable/data.table/master/vignettes/flights.csv&quot;</span> <span class="co">#在线文件需翻墙</span></span>
<span id="cb389-6"><a href="datatable-description.html#cb389-6" aria-hidden="true" tabindex="-1"></a>}</span>
<span id="cb389-7"><a href="datatable-description.html#cb389-7" aria-hidden="true" tabindex="-1"></a>flights <span class="ot">&lt;-</span> <span class="fu">fread</span>(input) <span class="co">#具体参数请参照文档  实际工作中可能会用到的encoding参数,编码 encoding=&#39;UTF-8&#39;</span></span>
<span id="cb389-8"><a href="datatable-description.html#cb389-8" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb389-9"><a href="datatable-description.html#cb389-9" aria-hidden="true" tabindex="-1"></a><span class="fu">head</span>(flights)</span>
<span id="cb389-10"><a href="datatable-description.html#cb389-10" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;    year month day dep_delay arr_delay carrier origin dest air_time distance</span></span>
<span id="cb389-11"><a href="datatable-description.html#cb389-11" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 1: 2014     1   1        14        13      AA    JFK  LAX      359     2475</span></span>
<span id="cb389-12"><a href="datatable-description.html#cb389-12" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 2: 2014     1   1        -3        13      AA    JFK  LAX      363     2475</span></span>
<span id="cb389-13"><a href="datatable-description.html#cb389-13" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 3: 2014     1   1         2         9      AA    JFK  LAX      351     2475</span></span>
<span id="cb389-14"><a href="datatable-description.html#cb389-14" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 4: 2014     1   1        -8       -26      AA    LGA  PBI      157     1035</span></span>
<span id="cb389-15"><a href="datatable-description.html#cb389-15" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 5: 2014     1   1         2         1      AA    JFK  LAX      350     2475</span></span>
<span id="cb389-16"><a href="datatable-description.html#cb389-16" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 6: 2014     1   1         4         0      AA    EWR  LAX      339     2454</span></span>
<span id="cb389-17"><a href="datatable-description.html#cb389-17" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;    hour</span></span>
<span id="cb389-18"><a href="datatable-description.html#cb389-18" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 1:    9</span></span>
<span id="cb389-19"><a href="datatable-description.html#cb389-19" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 2:   11</span></span>
<span id="cb389-20"><a href="datatable-description.html#cb389-20" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 3:   19</span></span>
<span id="cb389-21"><a href="datatable-description.html#cb389-21" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 4:    7</span></span>
<span id="cb389-22"><a href="datatable-description.html#cb389-22" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 5:   13</span></span>
<span id="cb389-23"><a href="datatable-description.html#cb389-23" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 6:   18</span></span></code></pre></div>
<p>本文读取本地文件,如果该数据集下载失败,可更改地址为(<a href="http://www.zhongyufei.com/datatable/data/flights.csv" class="uri">http://www.zhongyufei.com/datatable/data/flights.csv</a>)</p>
<div class="sourceCode" id="cb390"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb390-1"><a href="datatable-description.html#cb390-1" aria-hidden="true" tabindex="-1"></a>flights <span class="ot">&lt;-</span> <span class="fu">fread</span>(<span class="st">&quot;http://www.zhongyufei.com/Rbook/data/flights.csv&quot;</span>)</span></code></pre></div>
<p>数据集记录的是 2014 年,纽约市3大机场(分别为:JFK 肯尼迪国际机场、 LGA 拉瓜迪亚机场,和 EWR 纽瓦克自由国际机场)起飞的航班信息。</p>
<p>具体的记录信息(特征列)，包括起飞时间、到达时间、延误时长、航空公司、始发机场、目的机场、飞行时长，和飞行距离等。</p>
</div>
<div id="基本格式" class="section level3" number="7.1.2">
<h3><span class="header-section-number">7.1.2</span> 基本格式</h3>
<p><code>DT[i, j, by]</code>是data.table的基本样式，在不同位置上实现不同功能。</p>
<div class="figure">
<img src="https://gitee.com/zhongyufei/photo-bed/raw/pic/img/data.table-i-j-by%E4%BB%8B%E7%BB%8D.png" alt="" />
<p class="caption">i-j-by</p>
</div>
<div class="sourceCode" id="cb391"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb391-1"><a href="datatable-description.html#cb391-1" aria-hidden="true" tabindex="-1"></a>DT[i, j, by]</span>
<span id="cb391-2"><a href="datatable-description.html#cb391-2" aria-hidden="true" tabindex="-1"></a><span class="do">##   R:                 i                 j        by</span></span>
<span id="cb391-3"><a href="datatable-description.html#cb391-3" aria-hidden="true" tabindex="-1"></a><span class="do">## SQL:  where | order by   select | update  group by</span></span></code></pre></div>
<p>data.table个人理解主要有三大类参数,i参数做筛选,j参数做计算,by参数做分组.</p>
<p>拿Excel透视表类别,i位置参数当作『筛选』,by位置用来做汇总字段『行』,j位置当作『值』,如下所示:</p>
<div class="figure">
<img src="picture/data-table/01picture.png" alt="" />
<p class="caption">透视表截图</p>
</div>
<p>1.代码实例</p>
<p>代码求2014年6月,从各始发机场到各目的机场的飞行距离求和.</p>
<div class="sourceCode" id="cb392"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb392-1"><a href="datatable-description.html#cb392-1" aria-hidden="true" tabindex="-1"></a><span class="fu">library</span>(data.table)</span>
<span id="cb392-2"><a href="datatable-description.html#cb392-2" aria-hidden="true" tabindex="-1"></a>flights <span class="ot">&lt;-</span> <span class="fu">fread</span>(<span class="st">&quot;./data/flights.csv&quot;</span>)</span>
<span id="cb392-3"><a href="datatable-description.html#cb392-3" aria-hidden="true" tabindex="-1"></a>flights[year<span class="sc">==</span><span class="dv">2014</span> <span class="sc">&amp;</span> month<span class="sc">==</span><span class="dv">6</span>,.(求和项<span class="at">distance=</span><span class="fu">sum</span>(distance)),by<span class="ot">=</span>.(origin,dest)]</span>
<span id="cb392-4"><a href="datatable-description.html#cb392-4" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;      origin dest 求和项distance</span></span>
<span id="cb392-5"><a href="datatable-description.html#cb392-5" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;   1:    JFK  LAX        2663100</span></span>
<span id="cb392-6"><a href="datatable-description.html#cb392-6" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;   2:    JFK  DFW          82069</span></span>
<span id="cb392-7"><a href="datatable-description.html#cb392-7" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;   3:    JFK  LAS         795792</span></span>
<span id="cb392-8"><a href="datatable-description.html#cb392-8" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;   4:    JFK  SFO        1967946</span></span>
<span id="cb392-9"><a href="datatable-description.html#cb392-9" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;   5:    JFK  SAN         349778</span></span>
<span id="cb392-10"><a href="datatable-description.html#cb392-10" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;  ---                           </span></span>
<span id="cb392-11"><a href="datatable-description.html#cb392-11" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 191:    EWR  ANC          13480</span></span>
<span id="cb392-12"><a href="datatable-description.html#cb392-12" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 192:    EWR  BZN          15056</span></span>
<span id="cb392-13"><a href="datatable-description.html#cb392-13" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 193:    LGA  TVC           7205</span></span>
<span id="cb392-14"><a href="datatable-description.html#cb392-14" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 194:    LGA  BZN           3788</span></span>
<span id="cb392-15"><a href="datatable-description.html#cb392-15" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 195:    JFK  HYA            980</span></span></code></pre></div>
<p>2.代码解释</p>
<p>i 的部分：条件year==2014 和 month==6 ;</p>
<p>j 的部分：求和项distance=sum(distance)，写在.()中或者list()中；</p>
<p>by 的部分.(origin,dest),重点是写在.()中,和Excel透视表一一对应。</p>
<p>至于为什么要用.()包裹起来，最开始默认为格式强制要求。就这个问题我想说：大部分人可能觉得是比较“怪异”的用法，并且不理解，从而可能留下data.table不好用，很古怪的印象，但是我觉得任何东西存在即合理，你学一个东西总得接受一些你可能不认可的东西，这样可能才是真正的学习，就像拿Python来做数据分析，我刚开始觉得pandas很难用，很反人类，但是后来知道python代码可以直接打包封装成exe后，觉得真香，说这么多主要是想表达我们学会挑选合适的工具用，适应它，用好它就可以了。</p>
</div>
<div id="i-j-by-使用" class="section level3" number="7.1.3">
<h3><span class="header-section-number">7.1.3</span> i j by 使用</h3>
<p>使用data.table处理数据，接下来我们就用该函数读取数据演示i,j,by的简单使用。</p>
<div id="i行筛选" class="section level4" number="7.1.3.1">
<h4><span class="header-section-number">7.1.3.1</span> i行筛选</h4>
<p>行筛选是一种很常见的数据操作行为，类似我们Excel中的筛选，即按照一定条件筛选符合要求的数据。条件筛选一般分为单条件筛选、多条件筛选；</p>
<p>在筛选时涉及到条件判断，R语言中常用的条件判断分为逻辑运算、关系运算。常用的关系运算符 &gt;、 &lt;、==、!=、&gt;=、&lt;=分别代表大于、小于、等于、不等于、大于等于、小于等于。常用的逻辑运算符 &amp;、|、！等。</p>
<div class="sourceCode" id="cb393"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb393-1"><a href="datatable-description.html#cb393-1" aria-hidden="true" tabindex="-1"></a><span class="co">#单条件筛选</span></span>
<span id="cb393-2"><a href="datatable-description.html#cb393-2" aria-hidden="true" tabindex="-1"></a>filghts[year <span class="sc">==</span> <span class="dv">2014</span>] <span class="co">#筛选year==2014</span></span>
<span id="cb393-3"><a href="datatable-description.html#cb393-3" aria-hidden="true" tabindex="-1"></a><span class="co">#多条件筛选 用 &amp; 链接</span></span>
<span id="cb393-4"><a href="datatable-description.html#cb393-4" aria-hidden="true" tabindex="-1"></a>flights[ year <span class="sc">==</span> <span class="dv">2014</span> <span class="sc">&amp;</span> month <span class="sc">==</span> <span class="dv">6</span>] </span>
<span id="cb393-5"><a href="datatable-description.html#cb393-5" aria-hidden="true" tabindex="-1"></a><span class="co"># | 相当于中文条件或 </span></span>
<span id="cb393-6"><a href="datatable-description.html#cb393-6" aria-hidden="true" tabindex="-1"></a>flights[ month <span class="sc">==</span> <span class="dv">5</span> <span class="sc">|</span> month <span class="sc">==</span> <span class="dv">6</span>] </span>
<span id="cb393-7"><a href="datatable-description.html#cb393-7" aria-hidden="true" tabindex="-1"></a><span class="co"># %in% 类似sql中in用法</span></span>
<span id="cb393-8"><a href="datatable-description.html#cb393-8" aria-hidden="true" tabindex="-1"></a>flights[month <span class="sc">%in%</span> <span class="fu">c</span>(<span class="dv">1</span>,<span class="dv">3</span>,<span class="dv">5</span>,<span class="dv">7</span>,<span class="dv">9</span>)] </span>
<span id="cb393-9"><a href="datatable-description.html#cb393-9" aria-hidden="true" tabindex="-1"></a><span class="co"># %between% 类似sql中between and 用法</span></span>
<span id="cb393-10"><a href="datatable-description.html#cb393-10" aria-hidden="true" tabindex="-1"></a>flights[month <span class="sc">%between%</span> <span class="fu">c</span>(<span class="dv">1</span>,<span class="dv">7</span>)]</span></code></pre></div>
</div>
<div id="j列操作" class="section level4" number="7.1.3.2">
<h4><span class="header-section-number">7.1.3.2</span> j列操作</h4>
<p>数据集较大、字段较多时，由于无效信息较多可以做适当精选，这时需要我们筛选列。与sql中的select用法一致，即保留想要的字段。</p>
<p>.()或list()是data.table中的比较特殊的实现列筛选的用法。常规数字索引，字符向量索引同样有效。</p>
<div class="sourceCode" id="cb394"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb394-1"><a href="datatable-description.html#cb394-1" aria-hidden="true" tabindex="-1"></a><span class="co">#注意前面的. .()</span></span>
<span id="cb394-2"><a href="datatable-description.html#cb394-2" aria-hidden="true" tabindex="-1"></a>flights[,.(year,month,day,dep_delay,carrier,origin)] </span>
<span id="cb394-3"><a href="datatable-description.html#cb394-3" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;         year month day dep_delay carrier origin</span></span>
<span id="cb394-4"><a href="datatable-description.html#cb394-4" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;      1: 2014     1   1        14      AA    JFK</span></span>
<span id="cb394-5"><a href="datatable-description.html#cb394-5" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;      2: 2014     1   1        -3      AA    JFK</span></span>
<span id="cb394-6"><a href="datatable-description.html#cb394-6" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;      3: 2014     1   1         2      AA    JFK</span></span>
<span id="cb394-7"><a href="datatable-description.html#cb394-7" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;      4: 2014     1   1        -8      AA    LGA</span></span>
<span id="cb394-8"><a href="datatable-description.html#cb394-8" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;      5: 2014     1   1         2      AA    JFK</span></span>
<span id="cb394-9"><a href="datatable-description.html#cb394-9" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;     ---                                        </span></span>
<span id="cb394-10"><a href="datatable-description.html#cb394-10" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 253312: 2014    10  31         1      UA    LGA</span></span>
<span id="cb394-11"><a href="datatable-description.html#cb394-11" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 253313: 2014    10  31        -5      UA    EWR</span></span>
<span id="cb394-12"><a href="datatable-description.html#cb394-12" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 253314: 2014    10  31        -8      MQ    LGA</span></span>
<span id="cb394-13"><a href="datatable-description.html#cb394-13" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 253315: 2014    10  31        -4      MQ    LGA</span></span>
<span id="cb394-14"><a href="datatable-description.html#cb394-14" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 253316: 2014    10  31        -5      MQ    LGA</span></span>
<span id="cb394-15"><a href="datatable-description.html#cb394-15" aria-hidden="true" tabindex="-1"></a><span class="co"># flights[,list(year,month,day,dep_delay,carrier,origin)]  same above</span></span>
<span id="cb394-16"><a href="datatable-description.html#cb394-16" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb394-17"><a href="datatable-description.html#cb394-17" aria-hidden="true" tabindex="-1"></a><span class="co"># not run</span></span>
<span id="cb394-18"><a href="datatable-description.html#cb394-18" aria-hidden="true" tabindex="-1"></a><span class="co"># flights[,1:3]</span></span>
<span id="cb394-19"><a href="datatable-description.html#cb394-19" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb394-20"><a href="datatable-description.html#cb394-20" aria-hidden="true" tabindex="-1"></a><span class="co"># not run</span></span>
<span id="cb394-21"><a href="datatable-description.html#cb394-21" aria-hidden="true" tabindex="-1"></a><span class="co"># flights[,c(&#39;year&#39;,&#39;month&#39;,&#39;day&#39;)]</span></span></code></pre></div>
<p>setcolorder函数可以调整列的顺序，将常用的字段信息排在前面可以用过该函数实现。</p>
<div class="sourceCode" id="cb395"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb395-1"><a href="datatable-description.html#cb395-1" aria-hidden="true" tabindex="-1"></a><span class="co"># not run</span></span>
<span id="cb395-2"><a href="datatable-description.html#cb395-2" aria-hidden="true" tabindex="-1"></a><span class="co"># setcolorder(x = flights,neworder = c( &quot;month&quot;,&quot;day&quot;,&quot;dep_delay&quot; ,&quot;arr_delay&quot;,&quot;carrier&quot; )) </span></span>
<span id="cb395-3"><a href="datatable-description.html#cb395-3" aria-hidden="true" tabindex="-1"></a><span class="co"># 按照指定列顺序排序 其余字段保持不变,不是建立副本,是直接修改了flights 数据的列顺序</span></span></code></pre></div>
<ul>
<li>常规计算</li>
</ul>
<p>根据最开始的Excel透视表截图，我们想要获得如截图一样的结果该怎么实现呢？代码如下：</p>
<div class="sourceCode" id="cb396"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb396-1"><a href="datatable-description.html#cb396-1" aria-hidden="true" tabindex="-1"></a>flights[year<span class="sc">==</span><span class="dv">2014</span> <span class="sc">&amp;</span> month<span class="sc">==</span><span class="dv">6</span>,.(求和项<span class="at">distance=</span><span class="fu">sum</span>(distance),平均距离<span class="ot">=</span><span class="fu">mean</span>(distance)),by<span class="ot">=</span>.(origin,dest)]</span></code></pre></div>
<p>在i的位置做筛选，j的位置做计算，by指定分组字段。在j的位置可以做各种各样的计算，R中自带的函数，或者是自己定义的函数。</p>
<div class="sourceCode" id="cb397"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb397-1"><a href="datatable-description.html#cb397-1" aria-hidden="true" tabindex="-1"></a>myfun <span class="ot">&lt;-</span> <span class="cf">function</span>(x){</span>
<span id="cb397-2"><a href="datatable-description.html#cb397-2" aria-hidden="true" tabindex="-1"></a>    x<span class="sc">^</span><span class="dv">2</span><span class="sc">/</span><span class="dv">2</span></span>
<span id="cb397-3"><a href="datatable-description.html#cb397-3" aria-hidden="true" tabindex="-1"></a>}</span>
<span id="cb397-4"><a href="datatable-description.html#cb397-4" aria-hidden="true" tabindex="-1"></a>flights[year<span class="sc">==</span><span class="dv">2014</span> <span class="sc">&amp;</span> month<span class="sc">==</span><span class="dv">6</span>,.(<span class="fu">myfun</span>(distance)),by<span class="ot">=</span>.(origin,dest)]</span>
<span id="cb397-5"><a href="datatable-description.html#cb397-5" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;        origin dest      V1</span></span>
<span id="cb397-6"><a href="datatable-description.html#cb397-6" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;     1:    JFK  LAX 3062813</span></span>
<span id="cb397-7"><a href="datatable-description.html#cb397-7" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;     2:    JFK  LAX 3062813</span></span>
<span id="cb397-8"><a href="datatable-description.html#cb397-8" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;     3:    JFK  LAX 3062813</span></span>
<span id="cb397-9"><a href="datatable-description.html#cb397-9" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;     4:    JFK  LAX 3062813</span></span>
<span id="cb397-10"><a href="datatable-description.html#cb397-10" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;     5:    JFK  LAX 3062813</span></span>
<span id="cb397-11"><a href="datatable-description.html#cb397-11" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;    ---                    </span></span>
<span id="cb397-12"><a href="datatable-description.html#cb397-12" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 26484:    JFK  HYA   19208</span></span>
<span id="cb397-13"><a href="datatable-description.html#cb397-13" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 26485:    JFK  HYA   19208</span></span>
<span id="cb397-14"><a href="datatable-description.html#cb397-14" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 26486:    JFK  HYA   19208</span></span>
<span id="cb397-15"><a href="datatable-description.html#cb397-15" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 26487:    JFK  HYA   19208</span></span>
<span id="cb397-16"><a href="datatable-description.html#cb397-16" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 26488:    JFK  HYA   19208</span></span></code></pre></div>
</div>
<div id="by-分组" class="section level4" number="7.1.3.3">
<h4><span class="header-section-number">7.1.3.3</span> by 分组</h4>
<p>分组是按照某种分组实现一定条件下某种聚合方式的计算。分组可以是单字段，多字段以及条件字段等。</p>
<p>1.按月分组</p>
<div class="sourceCode" id="cb398"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb398-1"><a href="datatable-description.html#cb398-1" aria-hidden="true" tabindex="-1"></a>flights[,.(<span class="fu">sum</span>(distance)),by<span class="ot">=</span>.(month)]</span>
<span id="cb398-2"><a href="datatable-description.html#cb398-2" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;     month       V1</span></span>
<span id="cb398-3"><a href="datatable-description.html#cb398-3" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;  1:     1 25112563</span></span>
<span id="cb398-4"><a href="datatable-description.html#cb398-4" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;  2:     2 22840391</span></span>
<span id="cb398-5"><a href="datatable-description.html#cb398-5" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;  3:     3 28716598</span></span>
<span id="cb398-6"><a href="datatable-description.html#cb398-6" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;  4:     4 27816797</span></span>
<span id="cb398-7"><a href="datatable-description.html#cb398-7" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;  5:     5 28030020</span></span>
<span id="cb398-8"><a href="datatable-description.html#cb398-8" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;  6:     6 29093557</span></span>
<span id="cb398-9"><a href="datatable-description.html#cb398-9" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;  7:     7 30059175</span></span>
<span id="cb398-10"><a href="datatable-description.html#cb398-10" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;  8:     8 30322047</span></span>
<span id="cb398-11"><a href="datatable-description.html#cb398-11" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;  9:     9 27615097</span></span>
<span id="cb398-12"><a href="datatable-description.html#cb398-12" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 10:    10 28900834</span></span></code></pre></div>
<p>2.多条件分组</p>
<div class="sourceCode" id="cb399"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb399-1"><a href="datatable-description.html#cb399-1" aria-hidden="true" tabindex="-1"></a>dt <span class="ot">&lt;-</span> flights[,.(<span class="fu">sum</span>(distance)),by<span class="ot">=</span>.(carrier,origin)]</span>
<span id="cb399-2"><a href="datatable-description.html#cb399-2" aria-hidden="true" tabindex="-1"></a><span class="fu">head</span>(dt)</span>
<span id="cb399-3"><a href="datatable-description.html#cb399-3" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;    carrier origin       V1</span></span>
<span id="cb399-4"><a href="datatable-description.html#cb399-4" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 1:      AA    JFK 20492213</span></span>
<span id="cb399-5"><a href="datatable-description.html#cb399-5" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 2:      AA    LGA 12365282</span></span>
<span id="cb399-6"><a href="datatable-description.html#cb399-6" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 3:      AA    EWR  3550217</span></span>
<span id="cb399-7"><a href="datatable-description.html#cb399-7" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 4:      AS    EWR  1378748</span></span>
<span id="cb399-8"><a href="datatable-description.html#cb399-8" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 5:      B6    JFK 38117662</span></span>
<span id="cb399-9"><a href="datatable-description.html#cb399-9" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 6:      B6    EWR  4508574</span></span>
<span id="cb399-10"><a href="datatable-description.html#cb399-10" aria-hidden="true" tabindex="-1"></a><span class="co">#可直接重新命名</span></span>
<span id="cb399-11"><a href="datatable-description.html#cb399-11" aria-hidden="true" tabindex="-1"></a>dt <span class="ot">&lt;-</span> flights[,.(<span class="fu">sum</span>(distance)),by<span class="ot">=</span>.(<span class="at">newcol1 =</span> carrier,<span class="at">newcol2 =</span> origin)]</span>
<span id="cb399-12"><a href="datatable-description.html#cb399-12" aria-hidden="true" tabindex="-1"></a><span class="fu">head</span>(dt)</span>
<span id="cb399-13"><a href="datatable-description.html#cb399-13" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;    newcol1 newcol2       V1</span></span>
<span id="cb399-14"><a href="datatable-description.html#cb399-14" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 1:      AA     JFK 20492213</span></span>
<span id="cb399-15"><a href="datatable-description.html#cb399-15" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 2:      AA     LGA 12365282</span></span>
<span id="cb399-16"><a href="datatable-description.html#cb399-16" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 3:      AA     EWR  3550217</span></span>
<span id="cb399-17"><a href="datatable-description.html#cb399-17" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 4:      AS     EWR  1378748</span></span>
<span id="cb399-18"><a href="datatable-description.html#cb399-18" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 5:      B6     JFK 38117662</span></span>
<span id="cb399-19"><a href="datatable-description.html#cb399-19" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 6:      B6     EWR  4508574</span></span></code></pre></div>
<p>3.按月份是否大于6分组</p>
<p>即得到是否大于6的两类分组</p>
<div class="sourceCode" id="cb400"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb400-1"><a href="datatable-description.html#cb400-1" aria-hidden="true" tabindex="-1"></a>dt <span class="ot">&lt;-</span> flights[,.(<span class="fu">sum</span>(distance)),by<span class="ot">=</span>.(month<span class="sc">&gt;</span><span class="dv">6</span>)] <span class="co">#by里面可以做计算</span></span>
<span id="cb400-2"><a href="datatable-description.html#cb400-2" aria-hidden="true" tabindex="-1"></a><span class="fu">head</span>(dt)</span>
<span id="cb400-3"><a href="datatable-description.html#cb400-3" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;    month        V1</span></span>
<span id="cb400-4"><a href="datatable-description.html#cb400-4" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 1: FALSE 161609926</span></span>
<span id="cb400-5"><a href="datatable-description.html#cb400-5" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 2:  TRUE 116897153</span></span></code></pre></div>
</div>
</div>
<div id="行列筛选总结" class="section level3" number="7.1.4">
<h3><span class="header-section-number">7.1.4</span> 行列筛选总结</h3>
<p>行筛选在 i 的位置上进行, 列筛选在 j 的位置上进行;data.table中j的位置比较灵活多变，但是i的位置大部分时候都是进行条件筛选。我们通过上述的行列筛选已经大概知道data.table中i,j的用法。也就是我们常规数据清洗过程中的数据筛选过程，筛选符合要求的数据记录。</p>
<div class="sourceCode" id="cb401"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb401-1"><a href="datatable-description.html#cb401-1" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb401-2"><a href="datatable-description.html#cb401-2" aria-hidden="true" tabindex="-1"></a>dt <span class="ot">&lt;-</span> flights[ year <span class="sc">==</span> <span class="dv">2014</span> <span class="sc">&amp;</span> month <span class="sc">==</span> <span class="dv">6</span> <span class="sc">&amp;</span> day <span class="sc">&gt;=</span><span class="dv">15</span>,.(year,month,day,dep_delay,carrier,origin)] </span>
<span id="cb401-3"><a href="datatable-description.html#cb401-3" aria-hidden="true" tabindex="-1"></a><span class="fu">head</span>(dt)</span>
<span id="cb401-4"><a href="datatable-description.html#cb401-4" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt;    year month day dep_delay carrier origin</span></span>
<span id="cb401-5"><a href="datatable-description.html#cb401-5" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 1: 2014     6  15        -4      AA    JFK</span></span>
<span id="cb401-6"><a href="datatable-description.html#cb401-6" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 2: 2014     6  15        -8      AA    JFK</span></span>
<span id="cb401-7"><a href="datatable-description.html#cb401-7" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 3: 2014     6  15       -12      AA    JFK</span></span>
<span id="cb401-8"><a href="datatable-description.html#cb401-8" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 4: 2014     6  15        -4      AA    LGA</span></span>
<span id="cb401-9"><a href="datatable-description.html#cb401-9" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 5: 2014     6  15        -3      AA    JFK</span></span>
<span id="cb401-10"><a href="datatable-description.html#cb401-10" aria-hidden="true" tabindex="-1"></a><span class="co">#&gt; 6: 2014     6  15         5      AA    JFK</span></span></code></pre></div>
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